The use of nanofiltration (NF) membranes which are able to separate components of homogenous solutions based on molecular size has been increasing in recent years. Though most applications of NF membranes still pertain to filtration of aqueous mixtures, there is growing interest in applying nanofiltration to chemical processes conducted in organic solvents.
Applying NF to solvent-based processes requires membranes that do not degrade or dissolve in the presence of organic solvents. Such Organic Solvent Nanofiltration (OSN) membranes are manufactured utilizing various materials. A challenge in utilizing OSN membranes in chemical processes arises from the need of the membrane to simultaneously satisfy numerous criteria: the membrane should be solvent compatible, should be capable of performing the desired separation while maintaining a high filtration rate, should be effective for extended periods of time, and should be inert to the components in the process.
The last point has proven to be a particular challenge in processes that utilize reactive feedstocks and/or produce reactive products. As such, there remains a need for nanofiltration membranes that have low reactivity.